perf(x/staking/keeper): make Slash return early iff zero tokens to bu…

…rn (#18049)

CHANGELOG.md

@@ -52,6 +52,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (x/staking/keeper) [#]18049(https://github.com/cosmos/cosmos-sdk/pull/18049) return early if Slash encounters zero tokens to burn.
 * (x/staking/keeper) [#18035](https://github.com/cosmos/cosmos-sdk/pull/18035) Hoisted out of the redelegation loop, the non-changing validator and delegator addresses parsing.
 * (keyring) [#17913](https://github.com/cosmos/cosmos-sdk/pull/17913) Add `NewAutoCLIKeyring` for creating an AutoCLI keyring from a SDK keyring.
 * (codec) [#17913](https://github.com/cosmos/cosmos-sdk/pull/17913) `codectypes.NewAnyWithValue` supports proto v2 messages.

x/staking/keeper/slash.go

@@ -147,12 +147,26 @@ func (k Keeper) Slash(ctx context.Context, consAddr sdk.ConsAddress, infractionH
 	tokensToBurn := math.MinInt(remainingSlashAmount, validator.Tokens)
 	tokensToBurn = math.MaxInt(tokensToBurn, math.ZeroInt()) // defensive.
 
+	if tokensToBurn.IsZero() {
+		// Nothing to burn, we can end this route immediately! We also don't
+		// need to call the k.Hooks().BeforeValidatorSlashed hook as we won't
+		// be slashing at all.
+		logger.Info(
+			"no validator slashing because slash amount is zero",
+			"validator", validator.GetOperator(),
+			"slash_factor", slashFactor.String(),
+			"burned", tokensToBurn,
+			"validatorTokens", validator.Tokens,
+		)
+		return math.NewInt(0), nil
+	}
+
 	// we need to calculate the *effective* slash fraction for distribution
 	if validator.Tokens.IsPositive() {
 		effectiveFraction := math.LegacyNewDecFromInt(tokensToBurn).QuoRoundUp(math.LegacyNewDecFromInt(validator.Tokens))
 		// possible if power has changed
-		if effectiveFraction.GT(math.LegacyOneDec()) {
-			effectiveFraction = math.LegacyOneDec()
+		if oneDec := math.LegacyOneDec(); effectiveFraction.GT(oneDec) {
+			effectiveFraction = oneDec
 		}
 		// call the before-slashed hook
 		if err := k.Hooks().BeforeValidatorSlashed(ctx, operatorAddress, effectiveFraction); err != nil {